<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>http::async_read (2 of 2 overloads)</title>
<link rel="stylesheet" href="../../../../../../../doc/src/boostbook.css" type="text/css">
<meta name="generator" content="DocBook XSL Stylesheets V1.79.1">
<link rel="home" href="../../../index.html" title="Chapter&#160;1.&#160;Boost.Beast">
<link rel="up" href="../boost__beast__http__async_read.html" title="http::async_read">
<link rel="prev" href="overload1.html" title="http::async_read (1 of 2 overloads)">
<link rel="next" href="../boost__beast__http__async_read_header.html" title="http::async_read_header">
</head>
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
<table cellpadding="2" width="100%"><tr>
<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../../boost.png"></td>
<td align="center"><a href="../../../../../../../index.html">Home</a></td>
<td align="center"><a href="../../../../../../../libs/libraries.htm">Libraries</a></td>
<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
<td align="center"><a href="../../../../../../../more/index.htm">More</a></td>
</tr></table>
<hr>
<div class="spirit-nav">
<a accesskey="p" href="overload1.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../boost__beast__http__async_read.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="../boost__beast__http__async_read_header.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="beast.ref.boost__beast__http__async_read.overload2"></a><a class="link" href="overload2.html" title="http::async_read (2 of 2 overloads)">http::async_read
        (2 of 2 overloads)</a>
</h5></div></div></div>
<p>
          Read a complete message from a stream asynchronously.
        </p>
<h6>
<a name="beast.ref.boost__beast__http__async_read.overload2.h0"></a>
          <span class="phrase"><a name="beast.ref.boost__beast__http__async_read.overload2.synopsis"></a></span><a class="link" href="overload2.html#beast.ref.boost__beast__http__async_read.overload2.synopsis">Synopsis</a>
        </h6>
<p>
          Defined in header <code class="literal">&lt;<a href="../../../../../../../boost/beast/http/read.hpp" target="_top">boost/beast/http/read.hpp</a>&gt;</code>
        </p>
<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span>
    <span class="keyword">class</span> <a href="../../../../../../../doc/html/boost_asio/reference/AsyncReadStream.html" target="_top"><span class="bold"><strong>AsyncReadStream</strong></span></a><span class="special">,</span>
    <span class="keyword">class</span> <a class="link" href="../../concepts/DynamicBuffer.html" title="DynamicBuffer"><span class="bold"><strong>DynamicBuffer</strong></span></a><span class="special">,</span>
    <span class="keyword">bool</span> <span class="identifier">isRequest</span><span class="special">,</span>
    <span class="keyword">class</span> <a class="link" href="../../concepts/Body.html" title="Body"><span class="bold"><strong>Body</strong></span></a><span class="special">,</span>
    <span class="keyword">class</span> <span class="identifier">Allocator</span><span class="special">,</span>
    <span class="keyword">class</span> <a href="../../../../../../../doc/html/boost_asio/reference/ReadHandler.html" target="_top"><span class="bold"><strong>ReadHandler</strong></span></a><span class="special">&gt;</span>
<a href="../../../../../../../doc/html/boost_asio/reference/asynchronous_operations/automatic_deduction_of_initiating_function_return_type.html" target="_top"><span class="emphasis"><em>DEDUCED</em></span></a>
<span class="identifier">async_read</span><span class="special">(</span>
    <span class="identifier">AsyncReadStream</span><span class="special">&amp;</span> <span class="identifier">stream</span><span class="special">,</span>
    <span class="identifier">DynamicBuffer</span><span class="special">&amp;</span> <span class="identifier">buffer</span><span class="special">,</span>
    <span class="identifier">message</span><span class="special">&lt;</span> <span class="identifier">isRequest</span><span class="special">,</span> <span class="identifier">Body</span><span class="special">,</span> <span class="identifier">basic_fields</span><span class="special">&lt;</span> <span class="identifier">Allocator</span> <span class="special">&gt;&gt;&amp;</span> <span class="identifier">msg</span><span class="special">,</span>
    <span class="identifier">ReadHandler</span><span class="special">&amp;&amp;</span> <span class="identifier">handler</span><span class="special">);</span>
</pre>
<h6>
<a name="beast.ref.boost__beast__http__async_read.overload2.h1"></a>
          <span class="phrase"><a name="beast.ref.boost__beast__http__async_read.overload2.description"></a></span><a class="link" href="overload2.html#beast.ref.boost__beast__http__async_read.overload2.description">Description</a>
        </h6>
<p>
          This function is used to asynchronously read a complete message from a
          stream using HTTP/1. The function call always returns immediately. The
          asynchronous operation will continue until one of the following conditions
          is true:
        </p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
              The entire message is read.
            </li>
<li class="listitem">
              An error occurs.
            </li>
</ul></div>
<p>
          This operation is implemented in terms of one or more calls to the stream's
          <code class="computeroutput"><span class="identifier">async_read_some</span></code> function,
          and is known as a <span class="emphasis"><em>composed operation</em></span>. The program
          must ensure that the stream performs no other reads until this operation
          completes. The implementation may read additional octets that lie past
          the end of the message being read. This additional data is stored in the
          dynamic buffer, which must be retained for subsequent reads.
        </p>
<p>
          If the stream returns the error <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">error</span><span class="special">::</span><span class="identifier">eof</span></code>
          indicating the end of file during a read, the error returned from this
          function will be:
        </p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
              <a class="link" href="../boost__beast__http__error.html" title="http::error"><code class="computeroutput"><span class="identifier">http</span><span class="special">::</span><span class="identifier">end_of_stream</span></code></a>
              if no octets were parsed, or
            </li>
<li class="listitem">
              <a class="link" href="../boost__beast__http__error.html" title="http::error"><code class="computeroutput"><span class="identifier">http</span><span class="special">::</span><span class="identifier">partial_message</span></code></a>
              if any octets were parsed but the message was incomplete, otherwise:
            </li>
<li class="listitem">
              A successful result. A subsequent attempt to read will return <a class="link" href="../boost__beast__http__error.html" title="http::error"><code class="computeroutput"><span class="identifier">http</span><span class="special">::</span><span class="identifier">end_of_stream</span></code></a>
            </li>
</ul></div>
<h6>
<a name="beast.ref.boost__beast__http__async_read.overload2.h2"></a>
          <span class="phrase"><a name="beast.ref.boost__beast__http__async_read.overload2.parameters"></a></span><a class="link" href="overload2.html#beast.ref.boost__beast__http__async_read.overload2.parameters">Parameters</a>
        </h6>
<div class="informaltable"><table class="table">
<colgroup>
<col>
<col>
</colgroup>
<thead><tr>
<th>
                  <p>
                    Name
                  </p>
                </th>
<th>
                  <p>
                    Description
                  </p>
                </th>
</tr></thead>
<tbody>
<tr>
<td>
                  <p>
                    <code class="computeroutput"><span class="identifier">stream</span></code>
                  </p>
                </td>
<td>
                  <p>
                    The stream from which the data is to be read. The type must support
                    the AsyncReadStream concept.
                  </p>
                </td>
</tr>
<tr>
<td>
                  <p>
                    <code class="computeroutput"><span class="identifier">buffer</span></code>
                  </p>
                </td>
<td>
                  <p>
                    A DynamicBuffer holding additional bytes read by the implementation
                    from the stream. This is both an input and an output parameter;
                    on entry, any data in the dynamic buffer's input sequence will
                    be given to the parser first.
                  </p>
                </td>
</tr>
<tr>
<td>
                  <p>
                    <code class="computeroutput"><span class="identifier">msg</span></code>
                  </p>
                </td>
<td>
                  <p>
                    An object in which to store the message contents. This object
                    should not have previous contents, otherwise the behavior is
                    undefined. The type must be MoveAssignable and MoveConstructible.
                  </p>
                </td>
</tr>
</tbody>
</table></div>
<p>
          The object must remain valid at least until the handler is called; ownership
          is not transferred.
        </p>
<h6>
<a name="beast.ref.boost__beast__http__async_read.overload2.h3"></a>
          <span class="phrase"><a name="beast.ref.boost__beast__http__async_read.overload2.parameters0"></a></span><a class="link" href="overload2.html#beast.ref.boost__beast__http__async_read.overload2.parameters0">Parameters</a>
        </h6>
<div class="informaltable"><table class="table">
<colgroup>
<col>
<col>
</colgroup>
<thead><tr>
<th>
                  <p>
                    Name
                  </p>
                </th>
<th>
                  <p>
                    Description
                  </p>
                </th>
</tr></thead>
<tbody><tr>
<td>
                  <p>
                    <code class="computeroutput"><span class="identifier">handler</span></code>
                  </p>
                </td>
<td>
                  <p>
                    Invoked when the operation completes. The handler may be moved
                    or copied as needed. The equivalent function signature of the
                    handler must be:
                  </p>
<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"> <span class="keyword">void</span> <span class="identifier">handler</span><span class="special">(</span>
    <span class="identifier">error_code</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">error</span><span class="special">,</span>        <span class="comment">// result of operation,</span>
    <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">bytes_transferred</span>   <span class="comment">// the number of bytes transferred to the parser</span>
<span class="special">);</span>
</pre>
                  <p>
                    Regardless of whether the asynchronous operation completes immediately
                    or not, the handler will not be invoked from within this function.
                    Invocation of the handler will be performed in a manner equivalent
                    to using <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">asio</span><span class="special">::</span><span class="identifier">io_context</span><span class="special">::</span><span class="identifier">post</span></code>.
                  </p>
                </td>
</tr></tbody>
</table></div>
<p>
          Convenience header <code class="literal">&lt;<a href="../../../../../../../boost/beast/http.hpp" target="_top">boost/beast/http.hpp</a>&gt;</code>
        </p>
</div>
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
<td align="left"></td>
<td align="right"><div class="copyright-footer">Copyright &#169; 2016, 2017 Vinnie Falco<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
      </p>
</div></td>
</tr></table>
<hr>
<div class="spirit-nav">
<a accesskey="p" href="overload1.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../boost__beast__http__async_read.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="../boost__beast__http__async_read_header.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
</body>
</html>
